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IMPROVED HEAT SINK STRUCTURE FOR DYNAMIC BRAKE

Publishing Venue

The IP.com Prior Art Database

Abstract

The present invention includes an improved heat sink structure for dynamic brakes. The heat sink used on the dynamic brake IGBTs uses an air-cooled copper technology. The initial temperature starts at an air temperature, such as, 40 degree Celsius (C), which is much lower than the coolant temperature. The proposed heat sink has high thermal resistance for long continuous IGBT power dissipation. The proposed heat sink has high thermal mass, which is more important for the short time of dynamic brake operation.

Country

United States

Language

English (United States)

This text was extracted from a Microsoft Word document.

At least one non-text object (such as an image or picture) has been suppressed.

This is the abbreviated version, containing approximately
54% of the total text.

IMPROVED HEAT SINK
STRUCTURE FOR DYNAMIC BRAKE

BACKGROUND

The present invention relates generally to
a heat sink and more particularly to an improved heat sink structure for
dynamic brakes.

In general, dynamic brake insulated gate
bipolar transistors (IGBT) are typically off, with no power dissipation. When
the IGBTs need to operate, the dynamic brake IGBT operates for a very short
period of time with extreme power dissipation. The dynamic brakes are limited
by delta T, starting at an initial heat sink temperature, and becomes necessary
to shut-off when junction temperature reaches its limit. Since, IGBT operates
for a short time period, typically less than 1 second, low thermal resistance
is important only for the first half second. This implies that thermal mass of
heat sink is more important than thermal resistance.

A conventional heat sink technique used
for dynamic brakes IGBTs includes liquid-cooled aluminum technology. However,
the technique has several problems. Figure 1 depicts conventional IGBT
or heat sink structure for dynamic brakes.

Figure 1

As illustrated
in the above figure, the two main characteristics of conventional technique are
both limitations for a dynamic brake.
Firstly, initial temperature starts at the coolant temperature, which starts
at a relatively high temperature, such as, 60 degree Celsius(C). Secondly, the
dynamic brake has low thermal resistance for long continuous IGBT power
dissipation, but relatively low thermal mass.

Therefore there is a need in the art for a
new heat sink structure that is used for dynamic brakes.